Heat Exchanger With Integrated Thermal Bypass Valve

ABSTRACT

A heat exchanger apparatus containing a heat exchanger and a thermally actuated bypass valve. The heat exchanger having plurality of plates defining a first, a second and a bypass channels. A first fluid inlet manifold in fluid communication with the first and the bypass channels. The bypass valve positioned in the first fluid inlet manifold, and containing a sleeve having a first slot and a second slot, that permit fluid flow from a first fluid inlet to the bypass channel and to the first fluid inlet manifold, respectively. A drum positioned within the sleeve and movable from a first position to a second position. The drum having an aperture permitting first fluid flow to the first slot in the first position and to the second slot in the second position. An actuator engaging the drum and actuating it to move from the first position to the second position.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisionalpatent application No. 61/579,313, filed Dec. 22, 2011. The content ofthe above-noted patent application is hereby expressly incorporated byreference into the detailed description hereof.

FIELD OF THE INVENTION

The specification relates to a heat exchanger apparatus having anintegrated thermal bypass valve (TBV).

BACKGROUND OF THE INVENTION

Heat exchanger systems that vary the path of fluid flowing through theheat exchanger in response to a change in the characteristics (e.g.temperature, pressure, etc.) of the fluid are known. For example, WO94/29659 shows a plate-type oil cooler which has a pressure-responsivevalve assembly connected to the inlet of the oil-side to permit the oilto bypass the oil-side of the cooler when the pressure on the oil-sideof the cooler exceeds a predetermined value. Alternatively, U.S. Pat.No. 4,669,532 discloses a bimetallic valve which is disposed in theoil-side of an oil-cooler to permit the oil to bypass the oil-side ofthe cooler when the temperature of the oil is below a predeterminedvalue.

Additionally, there are numerous examples of heat exchanger systemswherein the flow rate of a fluid flowing through a heat exchanger iscontrolled according to the temperature of that of another fluid flowingthrough the heat exchanger. For example, German Laid-Open ApplicationNo. 196 37 818 and European Laid-Open Application No. 787 929 show twosuch systems wherein the flow of coolant through an oil cooler iscontrolled in response to the temperature of the oil flowing through theheat exchanger. In both of the systems, a thermostat is located upstreamof the inlet to measure the oil temperature before the oil enters theheat exchanger, although it is also known to control the flow of coolantthrough the heat exchanger system in response to the oil temperature asit exits the heat exchanger.

The problem with these systems is that they may take up considerableamounts of space, which is always at a premium in automotiveapplications, a primary use of this art. Additionally, these systems mayadd weight to the vehicle to which they are attached, possibly degradingfuel economy thereby. Furthermore, the environment surrounding thethermostat in these systems may affect the oil temperature reading,causing more or less coolant to be directed to the heat exchanger thanis actually necessary.

SUMMARY OF THE INVENTION

According to one aspect of the present application, there is provided aheat exchanger apparatus containing:

a heat exchanger, containing

-   -   a plurality of plates defining a first fluid channel, a second        fluid channel and a bypass channel;    -   first fluid inlet and outlet manifolds having first fluid inlet        and outlet, respectively, the first fluid inlet and outlet        manifolds being in fluid communication with the first fluid        channel; and, the first fluid inlet manifold also being in fluid        communication with the bypass channel; and

a thermal bypass valve positioned in the first fluid inlet manifold, thethermal bypass valve containing:

-   -   a sleeve having a first slot and a second slot, the first slot        permitting fluid flow from the first fluid inlet to the bypass        channel, and the second slot permitting fluid flow from the        first fluid inlet to the first fluid inlet manifold;    -   a drum positioned within the sleeve and slidably movable from a        first position to a second position, the drum having a first        aperture and one or more additional apertures, the first        aperture in fluid communication with the first fluid inlet and        the one or more additional apertures directing fluid to the        first slot or the second slot in the first or second position;        and    -   a thermal actuator engaging the drum and actuating the drum to        move from the first position to the second position in response        to the temperature of the first fluid.

According to another aspect of the present application, there isprovided a thermal bypass valve containing:

a sleeve having a first slot and a second slot;

a drum positioned within the sleeve and slidably movable from a firstposition to a second position, the drum having a first aperture and oneor more additional apertures, the first aperture in fluid communicationwith a first fluid inlet and the one or more additional aperturesdirecting fluid to the first slot or the second slot in the first orsecond position; and

a thermal actuator engaging the drum and actuating the drum to move fromthe first position to the second position in response to the temperatureof a first fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section of a portion of an oil-to-water (OTW)heater with an internally mounted thermal bypass valve (TBV) in the hot(i.e., oil hotter than the valve actuation set point temperature)condition, with oil flowing through the bypass channel;

FIG. 2 shows the OTW heater of FIG. 1 in the cold (oil colder than valveset point temperature) condition, with oil flowing through the heatexchanger;

FIG. 3 shows a cross-section of a portion of an OTW cooler with aninternally mounted TBV in the hot condition, with oil flowing throughthe heat exchanger;

FIG. 4 shows the OTW cooler of FIG. 3 in the cold condition, with oilflowing through the bypass channel; and

FIG. 5 shows a plan view of a thermal bypass valve in accordance withone embodiment, for use in a OTW cooler, with the drum in the firstposition.

FIG. 6 shows a thermal bypass valve in accordance with an embodiment,for use in a OTW cooler, with the drum in the first position.

FIG. 7 shows the sleeve and drum of a thermal bypass valve in accordancewith an embodiment shown in FIG. 6.

DESCRIPTION

The present description discloses, as an embodiment, a heat exchangerapparatus having a heat exchanger and a thermally actuated bypass valvepositioned within the heat exchanger.

An oil-to-water (OTW) heat exchanger, where a water-based heat exchangefluid such as engine coolant, is used to heat or cool oil. When combinedwith a suitable valve as disclosed herein, an OTW heat exchanger can beused either as an oil cooler, or oil warmer. In an OTW coolerconfiguration, where heat is transferred from the oil to the coolant,the oil flows through the heat exchanger in the hot state and bypassesthe heat exchanger in the cold state. In an OTW heater configuration,where heat is transferred from the coolant to the oil, the oil flowsthrough the heat exchanger in the cold state and bypasses the heatexchanger in the hot state. An OTW heater can help to accomplish rapidwarm-up of the oil from a cold start condition, knowing that the enginecoolant heats up more quickly than the oil.

In accordance with the embodiment of the present specification, thethermally actuated bypass valve (TBV) is internally mounted within theheat exchanger, and which can help to reduce the overall amount of spacerequired by the heat exchanger apparatus. In a further embodiment inaccordance with the specification, the heat exchanger apparatus includesa TBV mounted in an oil inlet fitting and/or oil inlet manifold of theheat exchanger.

The embodiments in accordance with the specification will now bedescribed with reference to the figures. FIGS. 1 and 2 show across-section of a portion of an OTW heater 10 containing a core 12 madeup of a plurality of dished heat exchanger plates. The type of platesused is not particularly limited and provide for a first fluid channel,a second fluid channel and a bypass channel 38. For instance, and asdisclosed in the embodiments in FIGS. 1 to 4, the first and second fluidchannels are formed by a plurality of nested dish plates, which in oneembodiment can be identical. The first fluid channel, as disclosedherein, can provide a passage for flow of oil, while the second fluidchannel can provide a passage for flow of a coolant or other liquid, forheat exchange. The bypass channel 38, as disclosed herein, can be formedby a generally flat plate 40 positioned above the nested dish plates anda bypass channel cover plate 18. The bottom of the heater 10 can beprovided with another nested flat bottom dish plate 42 to enclose theheater 10.

In one embodiment, the heater 10 can be provided with inlet and outletmanifolds for both the coolant and oil, but only the oil inlet manifold14 is shown in the drawings herein. The oil inlet manifold 14 and oiloutlet manifold are in fluid communication with oil flow passages incore 12 for flow of the first fluid. While the coolant inlet manifoldand coolant outlet manifold (not shown) are fluid communication with thesecond channel, permitting flow of the coolant. In the embodimentdisclosed, the manifold 14 is closed at its bottom and receives oilthrough its upper end from an oil inlet 44, to which can be coupled anoil inlet fitting 16. The fitting 16 is attached to the top of a bypasschannel cover plate 18, and is provided with an opening for the oilentry. As disclosed herein, in one embodiment, the bypass cover plate 18may cover the entire top of the core 12.

In the embodiment disclosed, the bypass channel 38 is present above thedished heat exchanger plates and close to the oil inlet fitting 16.However, the bypass channel 38 could also be positioned, for example andwithout limitation, below the core 12 of the heat exchanger plates withthe fitting 16 attached to a top plate of the dished heat exchangerplates.

Received inside the oil inlet fitting 16 and the oil inlet manifold 14is a thermal bypass valve (TBV) 19 having an outer sleeve 20, generallyin the form of a cylinder. The outer sleeve 20 is closed at its bottomend 46, which is further away from the oil inlet 44 or can be open andprovided with a flange extension for retaining a biasing means, asexplained further herein and as shown in the figures. In one embodimentand as disclosed in the figures, a major portion of the thermal bypassvalve is retained in position within the oil inlet manifold 14. In afurther embodiment, the top of sleeve 20 has a lip 22 which is retainedbetween the fitting 16 and cover plate 18, for affixing the sleeve 20and the TBV 19 in place in the oil inlet manifold 14. The outer sleeve20 is provided with upper slots 24 (or first slot) (encircled in FIGS.1-4 and 7) and lower slots 26 (or second slot) (encircled in FIGS. 1-4,6 and 7) for reasons which will become apparent below. The slotted outersleeve 20 is more clearly shown in FIGS. 5-7.

In the embodiment disclosed in the figures, the upper slots 24 of thesleeve permits fluid flow from the oil inlet 44 to the bypass channel38. While the lower slots 26 in the sleeve permit fluid flow from theoil inlet 44 to the oil inlet manifold 14, and from there, entering thecore 12 of the dished heat exchanger plates for heat exchange.

Located inside the outer sleeve 20 is a drum 28 that can slidably movewithin the sleeve 20 from a first position (FIGS. 2 and 4) to a secondposition (FIGS. 1 and 3). The drum 28 has a first aperture 48 (encircledin FIGS. 1-3) that is in fluid communication with the first fluid inlet44 (encircled in FIGS. 1-3) or opening in the oil inlet fitting 16 toallow the fluid, such as oil, to enter the drum. In addition, the drum28 is also provided with one or more apertures 36 (encircled in FIGS.1-4 and 7), such as a second aperture 52 or a second 52 and third 54aperture, for reasons which will become apparent below. The drum 28 isalso shown in FIGS. 5 and 6 positioned within the sleeve, while FIG. 7shows the drum 28 removed from the sleeve 20. The shape of the drum 28is not particularly limited, and in one embodiment, is generally in theform of a cylinder with a closed bottom, which is away from the oilinlet. In another embodiment, and as shown in the figures, the lower orbottom portion 50 of the drum 28 can have a particular profile, such asan arcuate profile, as described further herein.

The drum 28 contains a thermal actuator 30 which may be in the form of awax motor, and which, in one embodiment, is rigidly mounted at its upperend to the oil inlet fitting 16. The interior of the actuator 30contains a wax which expands when heated, such as for example, becauseof the temperature of the fluid. The actuator 30 includes a piston 32which extends when the wax is heated and can retract when the wax cools.Therefore the piston 32 is in the extended state in FIG. 1 when the oilis hot and is in the retracted state in FIG. 2 when the oil is cold.

The piston 32 engages the drum 28 such that the drum 28 moves downwardlyfrom a first position (as shown in FIGS. 2 and 4) to a second position(as shown in FIGS. 1 and 3) when the piston 32 extends. In theembodiment disclosed, the shape of the bottom of the drum 28 allows itto be operatively coupled to the piston 32 with the drum 28, such thatthe drum 28 moves in response to the piston 32. In the embodimentdisclosed in the figures, the arcuate profile of the bottom of the drum28 allows the piston 32 engage the drum 28, to operatively couple thepiston 32 to the drum 28.

In a further embodiment and as disclosed herein and shown in FIGS. 1 to4, a biasing means can be provided for biasing the drum 28 towards thefirst position. For example, a coil spring 34 between the outer sleeve20 and the drum 28 pushes the drum 28 upwardly when the piston 32retracts.

As noted above, the drum 28 is also provided with one or more apertures36 in addition to the first aperture 48, which is in fluid communicationwith the inlet 44. In one embodiment, as shown in FIGS. 1 and 2, thedrum 28 can be provided with second 52 and third 54 apertures(encircled); while in another embodiment, as shown in FIGS. 3, 4, 5 and7, the drum can be provided with a second 52 aperture (encircled) only.The second 52 and third 54 apertures (when present) can be provided as asingle opening or as multiple openings. Further, as shown in thefigures, the second 52 and third 54 apertures can be longitudinallyaligned with each other along the length of the drum 28. In analternative embodiment, the second 52 and third 54 apertures can beoffset (not shown) from each other along the length of the drum 28, solong as they allow fluid communication from the drum 28 to the slots ofthe outer sleeve 20 in different position of the drum, as disclosedherein.

In one embodiment of a OTW heater where the drum 28 is provided with asecond 52 and third 54 apertures, with the oil in the cold condition, asshown in FIG. 2, the piston is retracted and the drum 28 is raised, sothat the drum 28 blocks the upper slots 24 in the outer sleeve 20, andthe second aperture 52 in the drum 28 align with the lower slots 26 ofthe outer sleeve 20. Therefore, a closed flow path is created to blockoff bypass passage 38 from the oil inlet fitting 16 to core 12, and theoil enters the oil inlet manifold 14 through aligned second aperture 52and slots 26. Therefore the oil enters the manifold 14 and flows throughthe heat exchanger core 12, where it is heated by the coolant.

As the oil temperature increases, the temperature of the actuator 30increases and the piston 32 extends to the position shown in FIG. 1.This pushes the drum 28 down so that the second aperture 52 of the drum28 is blocked by the outer sleeve 20, and the top of the drum 28 nolonger blocks the upper slots 24 in the outer sleeve 20. Therefore, inthis position, the third aperture 54 aligns with the first slot 24 inthe outer sleeve 20 and the hot oil enters the bypass channel 38 betweenthe cover plate 18 and core 12, and does not enter the inlet manifold 14of heat exchanger 10.

FIGS. 3 and 4 show, as an embodiment, a cross-out section of a portionof an OTW cooler 10 which has most of the same elements as OTW heater 10described above. Like elements of cooler 10 are therefore described bylike reference numerals. One difference in such an embodiment is thatthe drum 28 can be provided with only the first 48 and second 52(encircled in FIGS. 3 and 4) apertures, with the first aperture 48 influid communication with the oil inlet 44 or opening in the oil inletfitting 16 to allow oil to enter the drum 28.

In the hot condition shown in FIG. 3, with the piston 32 extended, thesecond aperture 52 of drum 28 is aligned with the lower slots 26 ofouter sleeve 20, and the drum 28 blocks the upper slots 24. Therefore,the hot oil flows from inlet 44 to manifold 14, and then flows throughcore 12 where it transfers heat to the relatively cool coolant.

In the cold condition shown in FIG. 4, with the piston 32 is in theretracted position, the second aperture 52 of the drum 28 align with theupper slots 24 of the outer sleeve 20 to allow the oil to bypass theheat exchanger core 12. The drum 28 blocks oil flow to manifold 14, andtherefore oil is prevented from flowing through the lower slots 26 ofouter sleeve 20 and into manifold 14.

While the present invention has been described with reference to exampleembodiments and the accompanying drawings, it will be understood bythose skilled in the art that the invention is not limited to thepreferred embodiment and that various modifications could be madethereto without departing from the scope of the invention as defined bythe claims.

Table of reference numerals 10 heater 12 core 14 oil inlet manifold 16oil inlet fitting 18 bypass channel cover plate 19 thermal bypass valve(TBV) 20 outer sleeve 22 lip 24 upper slots 26 lower slots 28 drum 30thermal actuator 32 piston 34 coil spring 36 one or more apertures 38bypass channel 40 flat plate 42 bottom dish plate 44 oil inlet 46 bottomend of sleeve 48 first aperture 50 bottom portion of drum 52 secondaperture 54 third aperture

1. A heat exchanger apparatus comprising: a heat exchanger, comprising aplurality of plates defining a first fluid channel, a second fluidchannel and a bypass channel; first fluid inlet and outlet manifoldshaving first fluid inlet and outlet, respectively, the first fluid inletand outlet manifolds being in fluid communication with the first fluidchannel; and, the first fluid inlet manifold also being in fluidcommunication with the bypass channel; and a thermal bypass valvepositioned in the first fluid inlet manifold, the thermal bypass valvecomprising: a sleeve having a first slot and a second slot, the firstslot permitting fluid flow from the first fluid inlet to the bypasschannel, and the second slot permitting fluid flow from the first fluidinlet to the first fluid inlet manifold; a drum positioned within thesleeve and slidably movable from a first position to a second position,the drum having a first aperture and one or more additional apertures,the first aperture in fluid communication with the first fluid inlet andthe one or more additional apertures directing fluid to the first slotor the second slot in the first or second position; and a thermalactuator engaging the drum and actuating the drum to move from the firstposition to the second position in response to the temperature of thefirst fluid.
 2. The heat exchanger apparatus of claim 1, wherein the oneor more additional apertures comprises a second aperture, and the secondaperture permitting first fluid flow to the first slot in the firstposition and to the second slot in the second position.
 3. The heatexchanger apparatus of claim 1, wherein the one or more additionalapertures comprises a second aperture and a third aperture, wherein inthe first position, the second aperture permitting first fluid flow tothe second slot and the drum preventing flow to the first slot, and inthe second position, the third aperture permitting first fluid flow tothe first slot and the drum preventing flow to the second slot.
 4. Theheat exchanger apparatus according to claim 1, further comprising afitting at the first fluid inlet, and wherein the sleeve furthercomprises a lip positioned between the fitting and the first fluid inletfor affixing the sleeve in position.
 5. The heat exchanger according toclaim 1, wherein the actuator is coupled to the fitting.
 6. The heatexchanger according to claim 1, wherein the actuator comprises a motorcontaining a thermally expandable contractable material coupled to apiston.
 7. The heat exchanger according to claim 6, wherein the pistonengages the drum and moves from a first piston position to a secondpiston position and back to the first piston position in response to thethermal expansion and contraction of the thermally expandablecontractable material.
 8. The heat exchanger according to claim 6,wherein the thermally expandable contractable material is wax.
 9. Theheat exchanger according to claim 1, further comprising a biasing meansfor biasing the drum in the first position.
 10. The heat exchangeraccording to claim 9, wherein the biasing means is a spring.
 11. Theheat exchanger according to claim 1, wherein an end of the drum has anarcuate profile for operatively coupling the drum to the thermalactuator.
 12. A thermal bypass valve, comprising: a sleeve having afirst slot and a second slot; a drum positioned within the sleeve andslidably movable from a first position to a second position, the drumhaving a first aperture and one or more additional apertures, the firstaperture in fluid communication with a first fluid inlet and the one ormore additional apertures directing fluid to the first slot or thesecond slot in the first or second position; and a thermal actuatorengaging the drum and actuating the drum to move from the first positionto the second position in response to the temperature of a first fluid.13. The thermal bypass valve of claim 12, wherein the one or moreadditional apertures comprises a second aperture, and the secondaperture permitting first fluid flow to the first slot in the firstposition and to the second slot in the second position.
 14. The thermalbypass valve of claim 12, wherein the one or more additional aperturescomprises a second aperture and a third aperture, wherein in the firstposition, the second aperture permitting first fluid flow to the secondslot and the drum preventing flow to the first slot, and in the secondposition, the third aperture permitting first fluid flow to the firstslot and the drum preventing flow to the second slot.
 15. The thermalbypass valve according to claim 12, further comprising a lip foraffixing the sleeve in position.
 16. The thermal bypass valve accordingto claim 12, wherein the actuator comprises a motor containing athermally expandable contractable material coupled to a piston.
 17. Thethermal bypass valve according to claim 16, wherein the piston engagesthe drum and moves from a first piston position to a second pistonposition and back to the first piston position in response to thethermal expansion and contraction of the thermally expandablecontractable material.
 18. The thermal bypass valve according to claim16, wherein the thermally expandable contractable material is wax. 19.The thermal bypass valve according to claim 12, wherein an end of thedrum has an arcuate profile for operatively coupling the drum to thethermal actuator.